The invention relates to a method of producing concrete stones, in particular paving stones, building stones or the like, with a base part made of coarsely grained concrete, and a facing layer made of colored concrete mortar that solidly covers the top side of the base part, whereby the coarsely grained concrete is filled in a shaping tool and compacted in said shaping tool by vibrating and/or pressing, and in the lowered chamber of the shaping tool, the colored concrete mortar coming from a supply container is applied to the coarsely grained concrete as the facing layer and then compacted.
It is known to take dyed concrete mortar to be used as a facing layer for concrete stones out of a supply reservoir by means of gravity. If the facing layer is a multi-colored, for example a marbleized facing layer, mortar compounds are transported separated by color with conveyor belts and then filled into the supply container, and thereafter fed into the shaping tools either mixed or unmixed. It is known, furthermore, to feed mortar compounds of different colors into the supply container with help of additional containers associated with the supply container, and to then transfer said compounds from such a supply container into the molding tools. The known methods and devices have the common drawback that they require much expenditure in terms of machinery and manufacturing technology. In addition, the facing layers so produced show in many cases undefined color patterns due to unfavorable mixing resulting from the formation of heaps.
The problem of the invention is to provide a method that permits with low expenditure the manufacture of marbleized facing mortar for producing facing layers with a defined outward appearance that truthfully reflects the desired pattern.
Said problem is solved according to the invention in that the concrete mortar forming the facing layer is produced by layers dyed in different colors. Said layers are stored in the supply container at the top, where they are stacked in layers one on top of the other, then freely transported down jointly and simultaneously in partial sections by means of gravity, and on their way then collide with a baffle element projecting into the path of travel of the partial sections, and are then guided along said baffle element, guided by at least one deflecting curve, and are subsequently mixed with each other in order to form with the multi-colored concrete mortar on the coarsely grained concrete a marbleized facing layer that then needs to be compacted. The baffle element permits automatic adjustment of the deflecting curves in the supply container, and in particular predetermined mixtures of said partial sections owing to the transverse shifting of the partial sections occurring in the course of such adjustments. According to preferred steps of the method, the dyed layers are stored in the supply container stacked one on top of the other on a transversely adjustable slider, and can be freely moved downwardly by gravity with the help of said slider via an opening slot formed between the slider and the wall of the container, by moving the slider longitudinally. In this process, the layers are mixed with each other by the baffle element and the deflecting curves, and transferred in portions into the shaping tool as multi-colored concrete mortar by a closing member located at the bottom end of the supply container.
For carrying of the method, provision is made for a device which is characterized by an upright, hopper-shaped supply container with a transversely movable slider mounted in the supply container as a bearing element for layers of differently colored concrete mortar stacked one on top of the other; by an adjustable passage slot located between the slider and the wall of the supply container for partial sections of the layers being automatically movable downwardly by means of gravity; and by another slider located with a spacing beneath the slider serving as the bearing element, said other slider serving as a baffle and guide element for partial sections of the colored layers, and jointly forming with the wall of the container an additional, preferably variable passage slot for the partial sections; and in that the partial sections of the layers can be guided and mixed in the passage slots on deflecting curves; and furthermore by a displaceable and/or pivot-mounted closing member for quantitatively controlling portioned dispensing of the colored concrete mortar, said closing member being arranged on the supply container with a spacing below the slider serving as the baffle element. For the purpose of forming the deflecting curves and achieving offset passages, the two sliders are longitudinally displaceable against each other in the supply container, said two sliders forcibly guiding the concrete mortar in the deflecting curves. By changing the opening width of the passages it is possible to vary the deflecting curves and to obtain changes in the mixture. Furthermore, the passage formed by the closing member may be offset relative to the baffle element. Deflecting curves can be formed in this way that guide the concrete mortar through the supply container in opposite directions of rotation. Offsetting the passages on the sliders and on the closing member in this way may lead to a deflecting curve for the partial sections that extends, for example between the sliders in the clockwise direction, whereas an adjoining deflecting curve is adjusted against the clockwise direction between the sliders serving as the baffle element, and the closing member. It is understood that the colored concrete mortar can be guided also on deflecting curves rotating in opposite directions.
As a further development of the device, provision is made that the slider acting as the baffle element is designed in the form of a plane or curved molded part, which is arranged in the supply container in a fixed way or pivot-mounted therein. Furthermore, it is possible also the design the baffle element in some other way, for example in the form of a prism-shaped element arranged fixed or movable in the supply container, whereby said prismatic element preferably has a triangular cross section, for example in the form of a triangle with equally dimensioned legs or equal sides.
Finally, provision is made that the sliders serving as bearing and baffle elements, and the closing member for the partial sections of the colored layers of the concrete mortar are formed in any desired way by displaceable and/or by pivoting elements shaped in a plane or curved way.
A device for carrying out the method is shown in the figures, where